title: Prognostic significance of preoperative bowel obstruction in stage III colorectal cancer.
abstract: BACKGROUND
  Previous studies have suggested a detrimental prognostic effect of preoperative obstruction proximal to colorectal cancer (CRC). If such a detrimental effect is preserved in each stage of advanced (stage II or III) CRC, we can identify high-risk patients.
  
  
  METHODS
  We enrolled 641 patients with pathologically confirmed advanced CRC (stage II, n = 207; stage III, n = 434) who had undergone curative resection of the primary lesion. The association of preoperative obstruction with clinicopathologic parameters was evaluated. Kaplan-Meier analysis and Cox proportional hazard models were used to estimate the effect of preoperative obstruction on disease-free survival in each stage.
  
  
  RESULTS
  Preoperative obstruction was seen in 63 patients (9.8%) (stage II, n = 16; stage III, n = 47). Multivariable analysis showed that preoperative obstruction was significantly associated with preoperative elevation of carcinoembryonic antigen level in patients with colon cancer (odds ratio = 3.59; P < 0.001), while it was correlated with poor differentiation in patients with rectal cancer (odds ratio = 3.99; P = 0.016). Preoperative obstruction was a significant prognostic factor in stage III CRC (P < 0.001), but not in stage II disease. Multivariable prognostic analysis showed that preoperative obstruction was a remnant independent prognostic factor in stage III CRC. This finding was confirmed by separate analyses of colon and rectal cancer. Preoperative obstruction was associated with systemic recurrence (P = 0.003) rather than peritoneal or local recurrence.
  
  
  CONCLUSIONS
  These findings suggest that preoperative obstruction may predict worse long-term prognosis in patients with stage III CRC and may be a potential clinical marker to identify patients with high-risk stage III CRC.
authors.affiliation: Department of Surgery, Kitasato University School of Medicine, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Katoh
authors.forename: Keishi
authors.initials: K
authors.lastname: Yamashita
authors.forename: Guoqin
authors.initials: G
authors.lastname: Wang
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007415:Intestinal Obstruction / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D009367:Neoplasm Staging; D057234:Preoperative Period; D011379:Prognosis; D015996:Survival Rate